SQL. I'm continuously surprised by the ad-hoc manner in which devs use frameworks not understanding what the syntax they wrote means to the database. Many are

SQL. I'm continuously surprised by the ad-hoc manner in which devs use frameworks not understanding what the syntax they wrote means to the database. Many are confused by joins, or vs left-joins, and if a query runs slow have little idea how to index or change their schema to be more appropriate. While we're here I'd also say data modelling. The DB is not meant to have a row-to-screen/page cardinality matching, unless you're a startup using MongoDB (or other document store). The third one would be about API design. There are many blog posts that discuss one or two specific aspects of a particular API type (REST, gRPC, GraphQL) but it would be great to pick one of them and have it all lair out. There may be print books that cover the above, but certain important topics always seem to fall in the gaps, like how exactly does one bound their microservice context? Most books gloss over this with a hand-waving trio of Order, Product/Widget, Customer.